Image forming system, image forming apparatus, and feeding apparatus

ABSTRACT

An image forming apparatus comprises an accommodating unit that accommodates recording materials and a feeding unit that feeds an accommodated recording material, detects a fed recording material, and measures time from a predetermined timing until a recording material is detected. An information processing apparatus receives measured time data from the image forming apparatus, classifies the received plurality of time data into a first group and a second group in accordance with a length of time, selects a group for predicting a remaining life time of the feeding unit from the classified first group and second group, and predicts a remaining life time of the feeding unit using time data included in the selected group.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/111,598, filed on Dec. 4, 2020, which claims the benefit of andpriority to Japanese Patent Application No. 2019-224024, filed Dec. 11,2019, Japanese Patent Application No. 2020-104674, filed Jun. 17, 2020and Japanese Patent Application No. 2020-196336, filed Nov. 26, 2020,each of which is hereby incorporated by reference herein in theirentirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to an image forming system, an imageforming apparatus, and a feeding apparatus.

Description of the Related Art

An image forming apparatus such as a copy machine or a printer comprisesan accommodating unit on which a recording material (sheet) isaccommodated and a feeding mechanism that conveys a sheet that isaccommodated on the accommodating unit. In the feeding mechanism, aconfiguration in which the accommodated sheets are fed one by one usinga feeding roller by rotation of the feeding roller is common. Becausethe conveyance capability of the feeding roller decreases due toabrasion or deterioration of its surface through repeated conveyance ofsheets and the adhesion of paper dust, the feeding roller is treated asa consumable and is replaced by a user or repair worker. Accordingly, amethod is proposed in which the time it takes from the start of therotation of the feeding roller until a sheet arrives at a sensordisposed downstream (hereinafter, feeding time) in a conveyance path ismeasured and if the rate of occurrence of conveyance delay (hereinafter,feeding delay) exceeds a predetermined threshold, it is notified thatthere is a need to replace the feeding roller (refer to Japanese PatentLaid-Open No. 2018-100181).

However, in the above conventional technique, the state of the feedingroller cannot be known until the rate of occurrence of the feeding delayexceeds a predetermined threshold. Accordingly, it is difficult toascertain the replacement timing of the feeding roller at an earlystage, to improve the usage environment of the feeding roller before thereplacement timing is reached, and the like.

The purpose of the present invention is to provide a technique forpredicting the remaining life time of a feeding unit based on the usagestate of the feeding unit.

SUMMARY OF THE INVENTION

The present invention enables realization of predicting the remaininglife time of a feeding unit based on the usage state of the feedingunit.

One aspect of the present invention provides an image forming systemcomprising: an information processing apparatus and an image formingapparatus, wherein the image forming apparatus comprises anaccommodating unit configured to accommodate a recording material; afeeding unit configured to feed a recording material accommodated in theaccommodating unit; a detection unit configured to detect a recordingmaterial fed by the feeding unit; and a measuring unit configured tomeasure time from a predetermined timing until the detection unitdetects the recording material, and the information processing apparatuscomprises a reception unit configured to receive time data obtained bythe measuring unit from the image forming apparatus; a classificationunit configured to classify a plurality of the time data received by thereception unit into a first group and a second group in accordance witha length of time; and a selection unit configured to select a group forpredicting a remaining life time of the feeding unit from the firstgroup and the second group that are classified by the classificationunit; and a prediction unit configured to predict a remaining life timeof the feeding unit using the time data included in the group selectedby the selection unit.

Another aspect of the present invention provides an image formingapparatus, comprising: an accommodating unit configured to accommodate arecording material; a feeding unit configured to feed a recordingmaterial accommodated in the accommodating unit; a detection unitconfigured to detect a recording material fed by the feeding unit; ameasuring unit configured to measure time from a predetermined timinguntil the detection unit detects the recording material; aclassification unit configured to classify a plurality of the time dataobtained by the measuring unit into a first group and a second group inaccordance with a length of time; a selection unit configured to selecta group for predicting a remaining life time of the feeding unit fromthe first group and the second group that are classified by theclassification unit; and a prediction unit configured to predict aremaining life time of the feeding unit using the time data included inthe group selected by the selection unit.

Another aspect of the present invention provides a feeding apparatus,comprising: an accommodating unit configured to accommodate a recordingmaterial; a feeding unit configured to feed a recording materialaccommodated in the accommodating unit; a detection unit configured todetect a recording material fed by the feeding unit; a measuring unitconfigured to measure time from a predetermined timing until thedetection unit detects the recording material; an acquisition unitconfigured to divide a plurality of time data obtained by the measuringunit into two groups in accordance with a length of time and acquirefrom the plurality of time data included in a selected group among thetwo groups a reference time for determining a possibility that anabnormal state may occur when a recording material is fed by the feedingunit; and a determination unit configured to determine a possibilitythat the abnormal state may occur based on the reference time and theplurality of time data included in the selected group.

Still Another aspect of the present invention provides a feedingapparatus, comprising: an accommodating unit configured to accommodate arecording material; a feeding unit configured to feed a recordingmaterial accommodated in the accommodating unit; a detection unitconfigured to detect a recording material conveyed by the feeding unit;a driver unit configured to drive the feeding unit; a measuring unitconfigured to measure a driving amount by the driver unit from apredetermined timing until the detection unit detects a recordingmaterial; an acquisition unit configured to divide a plurality ofdriving amount data obtained by the measuring unit into two groups inaccordance with a size of a driving amount and acquire from theplurality of driving amount data included in a selected group among thetwo groups a reference amount for determining a possibility that anabnormal state may occur when a recording material is fed by the feedingunit; and a determination unit configured to determine a possibilitythat the abnormal state may occur based on the reference amount and theplurality of driving amount data included in the selected group.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments (with reference to theattached drawings).

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a schematic configuration diagram of an image formingapparatus in which a plurality of image forming units are arranged inparallel by adopting an intermediate transfer belt according to a firstembodiment.

FIG. 2A to FIG. 2C are a schematic cross-sectional view describing afeeding operation in the image forming apparatus according to the firstembodiment.

FIG. 3 is a view indicating an example of the transition of feeding timewhen the feeding operation of a recording material S is repeated in aconveyance mechanism as illustrated in FIG. 2A to FIG. 2C.

FIG. 4 is a block diagram describing a hardware configuration of theimage forming apparatus and a configuration of an image forming systemthat includes the image forming apparatus according to the firstembodiment.

FIG. 5 is a functional block diagram describing the functions of anengine control unit and a life time control unit according to the firstembodiment.

FIG. 6 is a view indicating an example of the number of sheets fed andfeeding time in the first embodiment.

FIG. 7 is a graph view indicating a feeding time profile in the firstembodiment.

FIG. 8 is a flowchart describing processing for obtaining the remaininglife time of a feeding roller in the image forming apparatus accordingto the first embodiment.

FIG. 9 is a graph view indicating a feeding time set in a secondembodiment.

FIG. 10 is a functional block diagram describing the functions of anengine control unit and a life time control unit according to the secondembodiment.

FIG. 11 is a flowchart describing processing for obtaining the remaininglife time of a feeding roller in the image forming apparatus accordingto the second embodiment.

FIG. 12 is a graph view indicating an example of an actual feeding timedata set in a third embodiment.

FIG. 13 is a functional block diagram describing the functions of anengine control unit and a life time control unit according to the thirdembodiment.

FIG. 14 is a flowchart describing processing for obtaining the remaininglife time of a feeding roller in the image forming apparatus accordingto the third embodiment.

FIG. 15 is a schematic configuration diagram of an image formingapparatus in which a plurality of image forming units are configured inparallel by adopting an intermediate transfer belt according to a fourthembodiment.

FIG. 16A and FIG. 16B are a schematic cross-sectional view describing aremaining amount detection operation for a recording material S in theimage forming apparatus according to the fourth embodiment.

FIG. 17 is a block diagram describing a hardware configuration of theimage forming apparatus and a configuration of an image forming systemthat includes the image forming apparatus according to the fourthembodiment.

FIG. 18 is a functional block diagram describing the functions of anengine control unit and a life time control unit according to a fifthembodiment.

FIG. 19 is a view indicating an example of the transition of feedingtime when the feeding operation is performed repeatedly, the recordingmaterial S being replenished whenever the recording material S that isaccommodated within a feeding cassette runs out, in the image formingapparatus according to the fourth embodiment.

FIG. 20 is a cross-sectional view illustrating the position of theleading edge of a recording material in accordance with the amount ofthe recording material in the image forming apparatus according to thefourth embodiment.

FIG. 21 is a graph view indicating an example of feeding time data inthe fourth embodiment.

FIG. 22 is a flowchart describing processing for obtaining the remaininglife time of a feeding roller in the image forming apparatus accordingto the fourth embodiment.

FIG. 23A to FIG. 23D are a view indicating an example of notification bytext string and examples of determination criteria for reliability,determination criteria for tendency change, and a table for correctingfeeding time data in accordance with the amount of recording materials.

FIG. 24 is a cross-sectional view of the image forming apparatus in thefifth and sixth embodiments.

FIG. 25A to FIG. 25C are a cross-sectional view of a feeding mechanismin the fifth and sixth embodiments.

FIG. 26 is a graph indicating a relationship of the number of sheets fedand feeding time in the fifth and sixth embodiments.

FIG. 27 is a graph indicating the frequency distribution of feedingtimes in the fifth embodiment.

FIG. 28 is a graph indicating the effect of the remaining amount in thecassette on feeding times in the fifth embodiment.

FIG. 29 is a graph indicating the relationship between the number ofsheets fed and feeding times for describing the calculation method of aslip index value in the fifth embodiment.

FIG. 30 is a graph indicating the relationship between the number ofsheets fed and the slip index value in the fifth embodiment.

FIG. 31 is a flowchart for determining the possibility of slippingoccurring in the fifth embodiment.

FIG. 32 is a graph view indicating a feeding time frequency distributionin a sixth embodiment.

FIG. 33 is a graph indicating the relationship between the number ofsheets fed and feeding times for describing the calculation method of adouble-feed index value in the sixth embodiment.

FIG. 34 is a graph indicating a relationship of the number of sheets fedand a double-feed index value in the sixth embodiment.

FIG. 35 is a flowchart for determining the possibility of double feedingoccurring in the sixth embodiment.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, embodiments will be described in detail with reference tothe attached drawings. Note, the following embodiments are not intendedto limit the scope of the claimed invention. Multiple features aredescribed in the embodiments, but limitation is not made to an inventionthat requires all such features, and multiple such features may becombined as appropriate. Furthermore, in the attached drawings, the samereference numerals are given to the same or similar configurations, andredundant description thereof is omitted.

FIG. 1 is a schematic configuration diagram of an image formingapparatus 100 in which a plurality of image forming units are comprisedin parallel by adopting an intermediate transfer belt according to afirst embodiment.

The image forming apparatus 100 is a tandem color laser beam printer andcan form (print) a color image by superimposing four colors oftoners—yellow (Y), magenta (M), cyan (C), and black (K). In FIG. 1, aconfiguration of image forming units corresponding to each color isindicated by adding subscripts Y, M, C, and K to reference numbers. Notethat in the following description, particularly in the description ofmembers for which yellow, magenta, cyan, and black do not need to bedistinguished, for the sake of descriptive convenience, the subscriptsY, M, C, and K of the reference numbers will be omitted.

Each process cartridge 5 has a toner container 6, a photosensitive drum1 which is an image carrier, a charging roller 2, a developing roller 3,a drum cleaning blade 4, and a waste toner container 7. A laser unit 8is disposed below the process cartridge 5, and the laser unit 8 performsexposure in relation to the photosensitive drum 1 based on an imagesignal. On the photosensitive drum 1, after the surface of the chargingroller 2 is charged to a potential having a predetermined negativepolarity by applying a voltage having a predetermined negative polarityto the charging roller 2, an electrostatic latent image that correspondsto each color is formed by the laser unit 8. A reversal development ofthis electrostatic latent image is performed by applying a voltage of apredetermined negative polarity to the developing roller 3, and Y, M, C,and K toner images are formed on their respective photosensitive drums1. Note that the toner used in the first embodiment is negativelycharged.

An intermediate transfer member unit has an intermediate transfer member11, a drive roller 12, a tension roller 13, and an opposing roller 15.Also, a primary transfer roller 10 is disposed inside the intermediatetransfer member 11 facing the photosensitive drum 1, and a transfervoltage is applied to the primary transfer roller 10 by a voltageapplication unit (not shown). A toner image that is formed on thephotosensitive drum 1 is primary-transferred onto the intermediatetransfer member 11 by rotating each photosensitive drum and theintermediate transfer member 11 in the direction of the arrow and thenapplying a positive voltage to the primary transfer roller 10. The tonerimages on the photosensitive drums 1 are primary-transferred onto theintermediate transfer member 11 in the order of Y, M, C, and K and thenare conveyed to a secondary transfer roller 14 in a state in which thetoner images of the four colors are overlapped.

A feeding mechanism 20 has a feeding roller 22 for feeding the recordingmaterial S from the inside of a feeding cassette (also calledaccommodation cassette) 21 on which the sheet-shaped recording materialS is accommodated and accommodated, a conveyance roller 23 for conveyingthe fed recording material S, and a separation roller 24 for separatingand conveying the recording material S one by one. Then, the recordingmaterial S that is conveyed from the feeding mechanism 20 is conveyed tothe secondary transfer roller 14 by a registration roller pair 25. Inorder to transfer the toner image from the intermediate transfer member11 to the recording material S, a voltage of positive polarity isapplied to the secondary transfer roller 14. As a result, the tonerimage on the intermediate transfer member 11 is secondarily transferredonto the conveyed recording material S. Then, the recording material Sto which the toner image is transferred is conveyed to a fixing device30 and is heated and pressurized by a fixing film 31 and a pressureroller 32 of the fixing device 30, and the toner image is fixed to thesurface of the recording material S. Then, the recording material S onwhich the image is fixed is discharged by a discharge roller pair 33.

At this time, the image forming apparatus determines whether or notconveyance failure such as an early arrival, a delay, or a jam of therecording material has occurred by using a conveyance path sensor 27. Ina case where it is determined that conveyance failure has occurred,display for notifying that conveyance failure has occurred in thedisplay unit (not shown) is performed. Also, a method for resolvingconveyance failure and the like is displayed as necessary.

Next, the feeding mechanism 20 according to the first embodiment will bedescribed in detail with reference to FIG. 2A to FIG. 2C.

FIG. 2 A to FIG. 2C are a schematic cross-sectional view describing afeeding operation in the image forming apparatus 100 according to thefirst embodiment.

FIG. 2A is a cross-sectional view of the feeding mechanism at a timingwhen a recording material S1 that is accommodated in the feedingcassette 21 and positioned at the top is fed. The recording material S1within the feeding cassette 21 is positioned by a trailing edgeregulating plate 26 within the feeding cassette 21, and the leading edgewhen the recording material S1 is fed is at a position that is indicatedby Ps. When a feeding operation is started, the feeding roller 22 andthe conveyance roller 23 each rotate, and the recording material S1starts to move in the rightward direction (feeding direction) in FIG. 2Aby the friction between the feeding roller 22 and the recording materialS1. Then, the recording material S1 reaches a separation nip Pn formedby the conveyance roller 23 and the separation roller 24.

At this time, as illustrated in FIG. 2B, frictional force also occursbetween recording materials S1 and S2, and the recording material S2 mayalso move. This separation nip Pn, when two or more recording materialsS1 and S2 are conveyed to the separation nip Pn by the rotation of thefeeding roller 22, has a function of separating the recording materialS2 and then sending only one recording material S1 downstream. A torquelimiter (not shown) is connected to the separation roller 24, and torqueas a resistance force is applied in a direction opposite to theconveyance direction of the recording material S1. This torque is set sothat when there is only one recording material S in the separation nipPn, the separation roller 24 rotates following the conveyance roller 23,but when two recording materials S enter the separation nip Pn, theseparation roller 24 stops. Accordingly, recording materials can beconveyed downstream one by one by the separation nip Pn.

Then, when the feeding roller 22 and the conveyance roller 23 furthercontinue to rotate, the recording material S1 passes through theregistration roller pair 25, and the leading edge of the recordingmaterial S1 reaches a position Pr where the leading edge is detected bythe conveyance path sensor 27 as illustrated in FIG. 2C. The time fromthe start of the feeding operation until the recording material S1reaches the conveyance path sensor 27 is feeding time.

FIG. 3 is a view indicating an example of the transition of feeding timewhen the feeding operation of a recording material S is repeated in aconveyance mechanism as illustrated in FIG. 2A to FIG. 2C.

As indicated in FIG. 3, when the feeding operation of the recordingmaterial S is repeated, the feeding time tends to lengthen in general.This is because, by repeating the feeding operation of the recordingmaterial, the feeding roller 22 is abraded and the frictional forcebetween the feeding roller 22 and the recording material decreases. Asdescribed above, when feeding is started from the separation nip Pn, thefeeding time is shorter, and when feeding is started from the positionPs of the leading edge of the recording material in the feeding cassette21, the feeding time is longer.

FIG. 4 is a block diagram describing a hardware configuration of theimage forming apparatus 100 and a configuration of an image formingsystem that includes the image forming apparatus 100 according to thefirst embodiment. This system includes a host computer 400, the imageforming apparatus 100, and a server (information processing apparatus)410. The host computer 400 has a main body unit 401 for instructing theimage forming apparatus 100 to print via a network and an operationdisplay unit 402 for accepting an operation of the user and performingdisplay that is related to the user. Here, the operation display unit402 that the host computer 400 has includes a display having a touchpanel function, a keyboard, a pointing device, and the like, which arenot shown.

The image forming apparatus 100 has a video controller 430, an operationdisplay unit 431, and a printer engine 420. The operation display unit431 that the image forming apparatus 100 has includes an operationpanel, an operation button, and the like, which are not shown. The videocontroller 430 transmits print data and a print instruction that weretransmitted from the host computer 400 to the printer engine 420. Theprinter engine 420 has an engine control unit 421 including a CPU 422, aROM 423, and a RAM 424, a system bus 425, and an IO port 426. The CPU422 executes a program by deploying the program and various data storedin the ROM 423 in the RAM 424 and using the RAM 424 as a work area. Theconfiguration elements described above can access the IO port 426 viathe system bus 425 which enables access in both directions. Theconveyance path sensor 27, a feeding motor 90, a feeding solenoid 91,and the like are connected to the IO port 426. The CPU 422 controlsthese devices via the IO port 426. Note that the devices connected tothe IO port 426 are not limited to the configuration in the firstembodiment.

A server 410 has a life time control unit 411 including a computingdevice 412 and a storage device 413 and is connected to the imageforming apparatus 100 via a network that enables communication in bothdirections. The computing device 412 executes a program stored in thestorage device 413 and performs reading and writing of various data. Thecomputing device 412 may directly allocate a RAM, an HDD, an SSD, or thelike to the CPU, the GPU, and the storage device 413 or may allocate avirtual environment such as a virtual machine. The life time controlunit 411 can perform transmission and reception of information with theengine control unit 421 via the video controller 430.

Next, functions of the engine control unit 421 and the life time controlunit 411 according to the first embodiment will be described withreference to FIG. 5. Note that the functions of the engine control unit421 are realized by the CPU 422 executing a program deployed in the RAM424. Also, the functions of the life time control unit 411 are realizedby the computing device 412 of the server 410 executing a program storedin the storage device 413. The engine control unit 421 has a functionrelated to feeding control and a function related to measuring of thefeeding time, and the life time control unit 411 has a function relatedto the prediction of the remaining life time (sometimes abbreviatedsimply as “life time”) of the feeding mechanism. Each will be describedin order.

FIG. 5 is a functional block diagram for describing functions of theengine control unit 421 and the life time control unit 411 according tothe first embodiment.

The engine control unit 421 has a feeding unit 501 and a driver unit 502as functions related to the feeding control. When the printer engine 420receives a print instruction, the feeding unit 501 instructs the driverunit 502 to perform a feeding operation. The driver unit 502, inaccordance with the instruction of the feeding unit 501, rotates theconveyance roller 23 and the separation roller 24 by rotationallydriving the feeding motor 90. Furthermore, at the timing of the start offeeding, by driving the feeding solenoid 91, the feeding roller 22 ismade to perform one rotation. By this operation, the recording materialsS that were pushed up in the feeding cassette 21 are separated, fed oneby one, and then conveyed to the conveyance path sensor 27.

Next, the engine control unit 421 has a measuring unit 503 and adetection unit 504 as functions related to measuring of the feedingtime. The measuring unit 503 measures the time from a timing when thefeeding unit 501 instructs a feeding operation until the leading edge ofthe recording material S reaches the conveyance path sensor 27. Thismeasuring is performed every time one sheet of the recording material Sis fed, and the measured time is stored in the RAM 424 as feeding timedata. The measuring unit 503 uses, for example, a timer incorporated inthe CPU 422 as a measuring unit for measuring time. The feeding timedata stored in the RAM 424 is also stored in the storage device 413 ofthe life time control unit 411 via the video controller 430. Thedetection unit 504, based on an input signal from the conveyance pathsensor 27, detects that the leading edge of the recording material S hasreached the conveyance path sensor 27.

The life time control unit 411 has a life time calculation unit 510 as afunction related to the prediction of the life time of the feedingmechanism. The life time calculation unit 510 has a classification unit511, a selection unit 512, and a prediction unit 513. The classificationunit 511 classifies feeding time data set that is stored in the storagedevice 413 into a plurality of subsets based on a predeterminedreference. In the first embodiment, the feeding time data set isclassified into a delay side data set and an early arrival side data setas indicated in FIG. 6.

FIG. 6 is a view indicating an example of the number of sheets fed andfeeding time in the first embodiment.

In the first embodiment, feeding time that is equal to or greater than1250 ms is the delay side data and feeding time that is less than 1250ms is the early arrival side data.

The selection unit 512 selects from the subsets that were classified bythe classification unit 511 a subset to use for calculating theremaining life time of the feeding mechanism. In the first embodiment,the delay side data set is selected. Then, the prediction unit 513,based on the subset selected by the selection unit 512, predicts afeeding time profile PF which represents the transition of feeding timein accordance with the number of sheets fed. Generally, feeding timeincreases as the feeding roller is abraded; therefore, it is possible topredict the remaining life time of the feeding roller from the change infeeding time.

FIG. 7 is a graph view indicating a feeding time profile in the firstembodiment.

In the first embodiment, as indicated in FIG. 7, the feeding timeprofile PF is acquired by extracting the top 10% of data from the delayside data set and then applying the result to a linear regression model.The feeding time profile PF in the first embodiment is a prediction ofthe feeding time when feeding is started from Ps and is represented by alinear function as indicated in Expression (1) when x is the number ofsheets fed, t is the feeding time, α is the slope, and β is theintercept.

PF: t=αx+β  Expression (1)

In this Expression (1), α and β are parameters that are decided by beingapplied to the linear regression model, and in FIGS. 6, α=70/300000 andβ=1380. By using this feeding time profile PF, it becomes possible topredict the transition of feeding time in accordance with the number ofsheets fed.

The life time calculation unit 510 acquires a remaining life time L ofthe feeding roller 22 using Expression (2) based on the maximum feedingtime Ts in a case where feeding is started from Ps and feeding time tthat is acquired by the feeding time profile PF. Then, the acquiredremaining life time L of the feeding roller is notified to the videocontroller 430.

$\begin{matrix}{{L(\%)} = {( {1 - \frac{t}{Ts}} ) \times 100}} & {{Expression}\mspace{14mu}(2)}\end{matrix}$

Note that in the first embodiment, the unit of feeding time t ismilliseconds, the unit of the number of sheets fed x is sheets, and theunit of remaining life time L of the feeding roller is percentage. Also,in the first embodiment, Ts=1500 ms which the maximum time that ispreset in which conveyance can be performed in a case where feeding isstarted from Ps.

Next, the operations of the engine control unit 421 and the life timecontrol unit 411 in the first embodiment will be described withreference to the flowchart in FIG. 8.

FIG. 8 is a flowchart describing processing for obtaining the remaininglife time of the feeding roller 22 in the image forming apparatus 100according to the first embodiment. Note that the processing indicated inthis flowchart is realized by the CPU 422 executing a program deployedin the RAM 424 and working together with a server control unit (acontrol unit (for example, life time control unit 411) of the server410).

This processing is started by the printer engine 420 receiving a printinstruction, and first in step S801, the CPU 422 starts the feedingoperation by the feeding unit 501 and the driver unit 502 and thenstarts the conveyance of the recording material S. Next, the processingproceeds to step S802 in which the CPU 422 increments the number ofsheets fed x (variable provided in the RAM 424) by 1. Next, theprocessing proceeds to step S803 in which the CPU 422 performs measuringof the feeding time by the measuring unit 503 and the detection unit504. In other words, based on the input signal from the conveyance pathsensor 27, the CPU 422 obtains the time when the leading edge of therecording material S reached the conveyance path sensor 27 and acquiresthe feeding time data by subtracting from that time the time when thefeeding operation was started. The CPU 422 transmits the acquiredfeeding time data to the server control unit. Then the processingproceeds to step S804 in which the computing device 412 stores thereceived feeding time data in the storage device 413.

Next, the processing proceeds to step S805 in which the computing device412 functions as the life time calculation unit 510 to determine whetheror not the feeding time data set that was stored in step S804 is equalto or greater than a predetermined amount and if it is not equal to orgreater than a predetermined amount, the processing proceeds to stepS811 and if it is equal to or greater than a predetermined amount, theprocessing proceeds to step S806 in which the computing device 412functions as the classification unit 511 to classify the feeding timedata set stored in the RAM 424 into the delay side data set and theearly arrival side data set. Then, the processing proceeds to step S807in which the computing device 412 functions as the selection unit 512and as described above with reference to FIG. 6, selects the feedingtime data set to be used for predicting remaining life time of thefeeding roller. Note that the predetermined amount in the firstembodiment is data in which the number of sheets fed is 500 sheets andthe feeding time data set to be selected is the delay side data set.

Then, the processing proceeds to step S808 in which the computing device412 functions as the prediction unit 513 and acquires the feeding timeprofile PF. For example, the following Expression (3) is an expressionthat indicates the acquired feeding time profile PF in relation to thefeeding time data set indicated in FIG. 6. Here, x indicates the numberof sheets fed.

$\begin{matrix}{{{PF}:t} = {{x( \frac{70}{300000} )} + 1380}} & {{Expression}\mspace{14mu}(3)}\end{matrix}$

Next, the processing proceeds to step S809 in which the computing device412 functions as the life time calculation unit 510 and acquires theremaining life time L of the feeding roller based on the feeding timeprofile PF and the maximum feeding time Ts=1500 ms in a case wherefeeding is started from the position Ps. In the first embodiment, theremaining life time L of the feeding roller is acquired using thefeeding time t that was acquired using Expression (3) and the followingExpression (4).

$\begin{matrix}{L = {( {1 - \frac{t}{1500}} ) \times 100}} & {{Expression}\mspace{14mu}(4)}\end{matrix}$

For example, because the feeding time t when the number of sheetsfed=300000 is t=1450, the remaining life time L of the feeding roller isL=3.33%.

Next, the processing proceeds to step S810 in which the computing device412 notifies to the video controller 430 the remaining life time L ofthe feeding roller which was acquired in step S809. The remaining lifetime L of the feeding roller is notified to the host computer 400 and aprinter management tool (not shown) as necessary by determination of thevideo controller 430. Then, finally, in step S811, the CPU 422determines whether or not there is a print instruction for the next pageand if there is a print instruction for the next page, returns again tostart the feeding operation in step S801 and if not, ends theprocessing.

Note that in the first embodiment, although a case in which there is onefeeding mechanism is indicated, the present invention may be applied toa configuration in which there is a plurality of feeding mechanisms. Ina case where there is a plurality of feeding mechanisms, operations ofthe engine control unit 421 and the life time control unit 411 areconducted separately for each feeding mechanism, and as a result, theremaining life times L of the feeding rollers are acquired separatelyfor each feeding mechanism.

As described above, according to the first embodiment, by accuratelypredicting the remaining life time of the feeding roller, it becomespossible to ascertain the replacement timing of the feeding roller at anearly stage. Also, because it is possible to know where the feedingroller is in its life before the replacement timing of the feedingroller is reached, it becomes possible to improve the usage state suchas changing the type of recording material before the replacement timingof the feeding roller.

Note that the present invention is not limited to the first embodiment.For example, a configuration may be taken so that the printer engine 420has the function of the life time control unit 411 of the server 410.Also, a clustering method such as a Gaussian mixture model or a K-meansclustering may be used as a method for classifying the feeding time dataset by the classification unit 511. Furthermore, a fitting method basedon a neural network, higher-order polynomial approximation, and the likemay be used for the acquisition of the feeding time profile PF by theprediction unit 513.

Also, in the first embodiment, although the unit of the remaining lifetime of the feeding roller 22 is percentage, it may be indicated by theunit of the number of sheets fed. Also, the notification of theremaining life time L of the feeding roller, as indicated in FIG. 23A,for example, may be notification of a text string in accordance with thevalue of the remaining life time L of the feeding roller. FIG. 23Aindicates an example of text strings to be notified in correspondencewith the remaining life time L of the feeding roller.

Second Embodiment

In the second embodiment, description will be given for an example inwhich the selection unit 512 selects a subset whose data reliability ishigh when selecting a subset to be used in the acquisition of remaininglife time of the feeding mechanism from subsets that were classified bythe classification unit 511. Because the hardware configuration, thesystem configuration, and the like of the image forming apparatusaccording to the second embodiment are the same as in the firstembodiment described above, only parts that are different from the firstembodiment will be described in the second embodiment.

As described above, in the first embodiment, the selection unit 512selected the delay side data set from the subsets that were classifiedby the classification unit 511. However, it may not always beappropriate to select the delay side data set depending on thecharacteristics of the recording material or the configuration of thefeeding cassette and the like. For example, assume that a subset asindicated in FIG. 9 was acquired as a result of the classification bythe classification unit 511.

FIG. 9 is a graph view indicating the set of feeding times in the secondembodiment.

In the example in FIG. 9, the delay side data set whose feeding time isequal to or greater than 1250 ms is greatly scattered, and if this delayside data set is used to predict the feeding time profile PF, there is apossibility that error may increase. Such a data set that is greatlyscattered can be treated as a data set whose reliability is low.Meanwhile, the early arrival side data set whose feeding time is lessthan 1250 ms is less scattered in comparison to the delay side data setand can be treated as a data set whose reliability is high.

In view of such a situation, the life time calculation unit 510 has areliability determination unit 1001 in the second embodiment. Thereliability determination unit 1001 determines the reliability of eachsubset that was classified by the classification unit 511 in accordancewith a predetermined determination criteria for determining reliability.The selection unit 512 selects a subset whose reliability is determinedto be high by the reliability determination unit 1001.

FIG. 10 is a functional block diagram for describing functions of theengine control unit 421 and the life time control unit 411 according tothe second embodiment. The parts that are common to FIG. 5 of the firstembodiment described above are indicated by the same reference numbers.The difference from FIG. 5 is in that the life time calculation unit 510has the reliability determination unit 1001. Note that a configurationmay be taken so that the printer engine 420 has the function of the lifetime control unit 411 of the server 410.

The determination criteria for reliability in the second embodiment willbe described with reference to FIG. 23B. FIG. 23B indicates the resultof determination of reliability in relation to a subset as indicated inFIG. 9. In the second embodiment, a subset whose variance is less than1000 (predetermined value) and the number of data is equal to or greaterthan 1000 (predetermined number) is determined to be high inreliability.

Next, the operations of the engine control unit 421 and the life timecontrol unit 411 in the second embodiment will be described withreference to the flowchart in FIG. 11.

FIG. 11 is a flowchart describing processing for obtaining the remaininglife time of the feeding roller 22 in the image forming apparatus 100according to the second embodiment. Note that the processing indicatedin this flowchart is realized by the CPU 422 executing a programdeployed in the RAM 424 and working together with the server controlunit. Note that in FIG. 11, the processing that is common to FIG. 8described above are given the same reference numbers, and thedescription thereof will be omitted.

In step S806, the computing device 412 functions as the classificationunit 511 and after classifying subsets of the feeding time data set,proceeds to step S1101. In step S1101, the computing device 412functions as the reliability determination unit 1001 to target allsubsets and determine the reliability of the feeding time data sets.Specifically, the computing device 412 determines if any of the delayside data and the early arrival side data is high in reliability inaccordance with the determination criteria for reliability as indicatedin FIG. 23B described above. Then, the processing proceeds to step S1102in which the computing device 412 determines whether there is a subsetwhose reliability is high and if there a subset whose reliability ishigh, proceeds to step S807 in which the computing device 412 functionsas the selection unit 512 to select a feeding time data set to be usedin the acquisition of remaining life time. Meanwhile, in step S1102, thecomputing device 412, if it determines that there is no subset whosereliability is high, proceeds to step S811 without performing theacquisition of the remaining life time of the feeding roller.

Note that in the second embodiment, the feeding time profile PF acquiredby the prediction unit 513 in step S808 is the prediction of feedingtime in a case where feeding is started from Pn in FIG. 3. Accordingly,the life time calculation unit 510, in step S809, acquires the remaininglife time L of the feeding roller using the following Expression (5)based on the maximum feeding time Tn in a case where feeding is startedfrom the position Pn and the feeding time t which is acquired by thefeeding time profile PF.

$\begin{matrix}{L = {( {1 - \frac{t}{Tn}} ) \times 100}} & {{Expression}\mspace{14mu}(5)}\end{matrix}$

Note that in the second embodiment, the unit of feeding time t ismilliseconds, the unit of the number of sheets fed x is sheets, and theunit of remaining life time L of the feeding roller is percentage. Also,Tn=1300 ms which is the maximum time that is preset in which conveyancecan be performed in a case where feeding is started from Pn.

As described above, according to the second embodiment, because theremaining life time of the feeding roller is predicted based on a subsetwhose data reliability is high, it becomes possible to predict theremaining life time of the feeding roller more accurately. As a result,it becomes possible to ascertain the replacement timing of the feedingroller at an early stage and also, because it is possible to know wherethe feeding roller is in its life before the replacement timing of thefeeding roller is reached, it becomes possible to improve the usagestate such as changing the type of recording material.

Note that the present invention is not limited to the second embodiment.For example, determination criteria for reliability may be changeddepending on factors such as the type of the recording material andtemperature and humidity of the environment.

Third Embodiment

In the third embodiment, the classification unit 511 of the life timecalculation unit 510 determines whether or not there is a tendencychange in the feeding time data set before classifying the feeding timedata set into a plurality of subsets based on a predetermined reference.Then, if there is a tendency change, a plurality of subsets areclassified based on the feeding time data set from where there is atendency change onward. Because the hardware configuration, the systemconfiguration, and the like of the image forming apparatus according tothe third embodiment are the same as in the first embodiment describedabove, only parts that are different from the first embodiment will bedescribed in the third embodiment. In the first embodiment describedabove, the classification unit 511 classified the feeding time data setthat was stored in the RAM 424 into a plurality of subsets by themeasuring unit 503 based on a predetermined reference. However, thetendency of the feeding time may change as indicated in FIG. 12 due tofactors such as the replacing of the feeding roller, the change of therecording material to be used, and the like.

FIG. 12 is a graph view indicating an example of an actual feeding timedata set in the third embodiment.

In FIG. 12, because the feeding roller was changed at a point in timewhen the number of sheets fed was 86517 sheets, the feeding time dataindicates tendencies that are different before and after thisreplacement. Accordingly, when the remaining life time of the feedingmechanism is predicted based on such a data set in which the feedingtime data that indicates different tendencies coexist, there is apossibility that the accuracy of the predicted remaining life time maylower. Accordingly, in the third embodiment, as illustrated in FIG. 13,the life time calculation unit 510 has a tendency change determinationunit 1301. This tendency change determination unit 1301 determines atendency change in the feeding time data set which was measured by themeasuring unit 503 and then was stored in the RAM 424 in accordance withthe determination criteria for determining whether or not there is atendency change. The classification unit 511, in a case where it isdetermined that there is a tendency change by the tendency changedetermination unit 1301, classifies into a plurality of subsets based onthe feeding time data set from a point in time when there was thetendency change onward.

FIG. 13 is a functional block diagram for describing functions of theengine control unit 421 and the life time control unit 411 according tothe third embodiment. The parts that are common to FIG. 5 of the firstembodiment described above are indicated by the same reference numbers.The difference from FIG. 5 is in that the life time calculation unit 510has the tendency change determination unit 1301.

The determination criteria for a tendency change in the third embodimentwill be described with reference to FIG. 23C. FIG. 23C indicates aresult of conducting tendency change determination on the feeding timedata set as indicated in FIG. 12, for example. In the third embodiment,in the feeding time data set, it is determined that a tendency changehas occurred in a case where the average value of the feeding time dataof the most recent 30 sheets has changed by 25 or more. According to thedetermination criteria for tendency change in the third embodiment, itis determined that a tendency change has occurred at a point in timewhen the number of sheets fed x=86517.

FIG. 14 is a flowchart describing processing for obtaining the remaininglife time of the feeding roller in the image forming apparatus 100according to the third embodiment. Note that the processing indicated inthis flowchart is realized by the CPU 422 executing a program deployedin the RAM 424 and working together with the server control unit. Notethat in FIG. 14, the processing that is common to FIG. 8 described aboveare given the same reference numbers, and the description thereof willbe omitted.

In step S805, the computing device 412, when it determines that thefeeding time data set is equal to or greater than a predeterminedamount, proceeds to step S1401. In step S1401, the computing device 412functions as the tendency change determination unit 1301 to determinethe presence or absence of tendency change in the feeding time data set.Specifically, the computing device 412, in accordance with determinationcriteria of the tendency change as indicated in FIG. 23C describedabove, obtains the average value of the feeding time data of the mostrecent 30 sheets and determines, in a case where the feeding time datahas changed by 25 ms or more, that the tendency has changed.

In step S1402, the computing device 412 determines whether or not thereis a tendency change in the feeding time data set and if it determinesthat there is a tendency change, proceeds to step S1403 in which thecomputing device 412 extracts data from a point in time when there wasthe tendency change in the feeding time data set onward. For example, asindicated in FIG. 23C, in a case where the computing device 412determines that there was a tendency change within a predetermined time(for example, the most recent 30 minutes) whose amount of change wasequal to or greater than a predetermined amount, and extracts thefeeding time data from when there was the tendency change when thenumber of sheets fed x=86517 onward. Then, the processing proceeds tostep S806 in which the computing device 412 functions as theclassification unit 511 and classifies the extracted feeding time dataset into the delay side data set and the early arrival side data set.Note that in step S1402, the computing device 412, when it determinesthat there is no tendency change, proceeds to step S806 and thenexecutes the same processing as in the first embodiment.

As described above, according to the third embodiment, in a case wherethe feeding time data has changed greatly due to the replacing of thefeeding roller and the like, for example, it is possible to predict theremaining life time of the feeding roller by using the feeding time datafrom the change onward. As a result, it becomes possible to predict theremaining life time of the feeding roller more accurately. As a result,it becomes possible to ascertain the replacement timing of the feedingroller at an early stage and also, because it is possible to know wherethe feeding roller is in its life before the replacement timing of thefeeding roller is reached, it becomes possible to improve the usagestate such as changing the type of recording material.

Note that the present invention is not limited to the third embodiment.For example, in addition to the configuration of the third embodiment,tendency change determination indicated in the second embodiment may beperformed. Also, a configuration may be taken so as to be able to detectseparately a change of the type of the recording material, the replacingof the feeding roller, and the like and to perform tendency changedetermination based on that detection result.

Fourth Embodiment

Next, a fourth embodiment of the present invention will be described. Inthe fourth embodiment, description will be given for an example in whichthe feeding time it takes for the recording material S1 positioned atthe top to reach the conveyance path sensor 27 is corrected inaccordance with the amount of the recording material S that isaccommodated within the feeding cassette 21. Because the hardwareconfiguration, the system configuration, and the like of the imageforming apparatus 100 according to the third embodiment are basicallythe same as in the first embodiment described above, only parts that aredifferent from the first embodiment will be described in the thirdembodiment.

FIG. 15 is a schematic configuration diagram of the image formingapparatus 100 in which a plurality of image forming units are configuredin parallel by adopting an intermediate transfer belt according to thefourth embodiment. In FIG. 15, the parts that are common to theconfiguration in FIG. 1 according to the first embodiment describedabove are given the same reference numbers, and the description thereofwill be omitted.

In FIG. 15, a recording material detection sensor 28 and a feedingcassette absence/presence detection sensor 29 have been added inrelation to the configuration in FIG. 1. The recording materialdetection sensor 28 detects the amount of the recording material S thatis accommodated within the feeding cassette 21. Also, theabsence/presence detection sensor 29 of the feeding cassette detectswhether or not the feeding cassette 21 that accommodates the recordingmaterial S is attached to the image forming apparatus 100.

Next, a detection mechanism for the remaining amount of the recordingmaterial in the fourth embodiment will be described with reference toFIG. 16A and FIG. 16B.

FIG. 16A and FIG. 16B are a schematic cross-sectional view describing adetection operation for the remaining amount of the recording material Sin the image forming apparatus 100 according to the fourth embodiment.

FIG. 16A is a cross-sectional view of the feeding mechanism at a pointin time when the feeding cassette 21 accommodating the recordingmaterial S is connected to the image forming apparatus 100. The feedingmechanism 20, when it detects that the feeding cassette 21 is connectedto the image forming apparatus 100 by the absence/presence detectionsensor 29 of the feeding cassette, causes a feeding cassette bottomplate 19 to rise by driving a lift up motor (not shown) until therecording material S1 positioned at the top is sensed by the recordingmaterial detection sensor 28 as illustrated in FIG. 16B. As a result,the recording material S is pushed up by the feeding cassette bottomplate 19 centered on a center of oscillation 40 of the feeding cassettebottom plate 19 and then is moved to a position where the feeding can beperformed by the feeding roller 22. At this time, the feeding mechanism20 can detect the amount of the recording material S that isaccommodated within the feeding cassette 21 based on the amount of timethe lift up motor was driven.

Here, the amount of the recording material S is indicated by percentage,and this amount is converted based on the driving time of the lift upmotor, which is a preset reference. In a case where the amount of therecording material S is large, the recording material S1 is detected bythe recording material detection sensor 28 immediately after driving thelift up motor; therefore it is possible to detect that the amount of therecording material S is large. Meanwhile, in a case where the amount ofthe recording material S is small, the recording material S1 is detectedby the recording material detection sensor 28 a while after driving thelift up motor; therefore it is possible to detect that the amount of therecording material S is small. Then, the feeding mechanism 20, bydecreasing the amount of the detected recording material S every timethe recording material S is fed one by one from the feeding cassette 21,can predict the amount of the recording material S that is accommodatedwithin the feeding cassette 21 at all times. Note that in the fourthembodiment, although description was given for a method for detectingthe amount of the recording material S using the driving time of thelift up motor, the present invention is not limited to this, and anothermethod may be used for detection such as detecting by another sensor theamount that the feeding cassette bottom plate 19 is pushed up, forexample, as long as the amount of the recording material S can bedetected.

FIG. 17 is a block diagram describing a hardware configuration of theimage forming apparatus 100 and a configuration of an image formingsystem that includes the image forming apparatus 100 according to thefourth embodiment. In FIG. 17, the parts that are common to FIG. 4according to the first embodiment described above are given the samereference numbers, and the description thereof will be omitted. In thefourth embodiment, the recording material detection sensor 28, theabsence/presence detection sensor 29 of the feeding cassette, and a liftup motor 92 have been added in relation to the configuration in FIG. 4.In the configuration the fourth embodiment, the recording materialdetection sensor 28, the absence/presence detection sensor 29 of thefeeding cassette, and the lift up motor 92 are connected to the 10 port426 of the printer engine 420 as illustrated in FIG. 17. The CPU 422controls these devices via this the 10 port 426.

FIG. 18 is a functional block diagram for describing functions of theengine control unit 421 and the life time control unit 411 according toa fifth embodiment. In FIG. 18, the parts that are common to FIG. 5according to the first embodiment described above are given the samereference numbers, and the description thereof will be omitted.

Here, a correction unit 1801 has a recording material remaining amountdetection unit 1802 as a function for correcting the feeding timemeasured by the measuring unit 503. The correction unit 1801 correctsand then stores in the RAM (memory) 424 the feeding time from a timingwhen the feeding unit 501 instructs a feeding operation until theleading edge of the recording material S reaches the conveyance pathsensor 27 based on the amount of the recording material S that isaccommodated within the feeding cassette 21 which was detected by therecording material remaining amount detection unit 1802. The feedingtime stored in the RAM 424 is also stored in the storage device 413 ofthe life time control unit 411 via the video controller 430. Note thatthe method for correcting the feeding time by the correction unit 1801in the fourth embodiment will be described later. The recording materialremaining amount detection unit 1802, when it detects by theabsence/presence detection sensor 29 of the feeding cassette that thefeeding cassette 21 is attached to the image forming apparatus 100,drives the lift up motor 92, senses by the recording material detectionsensor 28 the recording material S1 that is positioned at the top, andthen detects the amount of the recording material S based on the result.

Next, correction control by the correction unit 1801 which is an aspectof the fourth embodiment will be described.

FIG. 19 is a view indicating an example of the transition of feedingtime when the feeding operation is performed repeatedly, the recordingmaterial S being replenished whenever the recording material S that isaccommodated within the feeding cassette 21 runs out, in the imageforming apparatus 100 according to the fourth embodiment.

As indicated in FIG. 19, feeding time increases or decreases as theamount of the recording material S that is accommodated within thefeeding cassette 21 decreases. This is because, as illustrated in FIG.20, the position of the leading edge of the recording material S changeswhen the recording material S is pushed up to a position where feedingcan be performed by the feeding cassette bottom plate 19 in accordancewith the distance from the center of oscillation 40 of the feedingcassette bottom plate 19 to a position of the leading edge of therecording material.

FIG. 20 is a cross-sectional view illustrating the position of theleading edge of a recording material in accordance with the amount ofthe recording material in the image forming apparatus 100 according tothe fourth embodiment.

In other words, the feeding time changes because the position of theleading edge of the recording material S changes in accordance with theamount of the recording material S that is accommodated within thefeeding cassette 21. Therefore, in the correction unit 1801 according toa fourth embodiment, as indicated in FIG. 23D, the feeding time iscorrected in accordance with the remaining amount of the recordingmaterial sensed by the recording material remaining amount detectionunit 1802.

Because as the amount of the recording material decreases, the positionof the leading edge of the recording material changes and the feedingtime shortens, feeding time t_a which was measured by the measuring unit503 and feeding time t_b after correction, using the followingExpression (6) based on an amount of correction Z of the feeding timeindicated in FIG. 23D, are acquired.

t_b=t_a+Z  Expression (6)

Note that in the fourth embodiment, as indicated in FIG. 23D, althoughthe unit of the amount of the recording material is percentage, the unitmay be the number of sheets of the recording material and although thefeeding time is corrected by a unit of time, the unit may be a unit ofdistance. Also, although the amount of correction by which the feedingtime is corrected is stored in a table format as in FIG. 23D, thefeeding time may be corrected by a calculation equation.

Also, although in the fourth embodiment, description was given for anexample in which the feeding time is corrected for any case, correctionby the correction unit 1801 may be invalid, in other words, the feedingtime may not need to be corrected, depending on the type of therecording material.

This is because, as indicated in FIG. 21, for example, depending on thetype of the recording material, a slip or the like may occur whenfeeding the recording material S1 by the feeding roller 22 and thefeeding time may not be stable. FIG. 21 is a graph view indicating anexample of feeding time data in the fourth embodiment.

FIG. 22 is a flowchart describing processing for obtaining the remaininglife time of the feeding roller in the image forming apparatus 100according to the fourth embodiment. Note that the processing indicatedin this flowchart is realized by the CPU 422 executing a programdeployed in the RAM 424 and working together with the server controlunit. Note that in FIG. 22, the processing that is common to FIG. 8described above are given the same reference numbers, and thedescription thereof will be omitted.

In step S804, the CPU 422 stores in the RAM 424 the measurement resultby the measuring unit 503 and the detection unit 504 and then proceedsto step S2201. In step S2201, the CPU 422 functions as the correctionunit 1801 to correct the feeding time data based on the amount of therecording material S that is accommodated within the feeding cassette 21detected by the recording material remaining amount detection unit 1802.The CPU 422 transmits the corrected feeding time data to the servercontrol unit. The computing device 412 stores in the storage device 413the received correction result.

Specifically, the computing device 412 refers to the feeding timecorrection table indicated in FIG. 23D described above and then correctsthe feeding time in accordance with the amount of the recordingmaterial. Then, in step S806 onward, the computing device 412 functionsas the life time calculation unit 510, and the remaining life time L ofthe feeding roller is acquired using the corrected feeding time datawhen the remaining life time of the feeding roller is predicted based onthe feeding time data set.

As explained above, according to the fourth embodiment, by correctingthe variation of the feeding time data based on the amount of therecording material, it becomes possible to accurately predict theremaining life time of the feeding roller. Also, it becomes possible toascertain the replacement timing of the feeding roller at an early stageand also, because it is possible to ascertain what stage the feedingroller is in its life before the replacement timing of the feedingroller is reached, it becomes possible to improve the usage state suchas changing the type of recording material.

Note that the present invention is not limited to the fourth embodiment.Although the correction of the feeding time is conducted by the imageforming apparatus 100, the amount of the recording material may benotified to the server and then the feeding time data may be correctedon that server, for example. Also, although in the fourth embodiment,description was given for a method for predicting of the remaining lifetime of the feeding roller from the feeding time profile, the presentinvention is not limited to this, and any method may be used as long asthe method is a method for predicting the remaining life time of thefeeding roller from the feeding time.

Fifth Embodiment

In the present embodiment, description will be given regarding a methodfor determining the possibility that the recording material may slipduring the feeding operation.

[Description of Image Forming Apparatus]

An electrophotographic printer PR (image forming apparatus) will bedescribed as an example of a feeding apparatus that can adopt thepresent embodiment. FIG. 24 is a schematic configuration diagram of theprinter PR.

The printer PR is a tandem color laser beam printer and is configured tobe able to output a color image by superimposing four colors oftoners—yellow (Y), magenta (M), cyan (C), and black (K). Note that inthe following description, particularly in the description of membersfor which yellow, magenta, cyan, and black do not need to bedistinguished, for the sake of descriptive convenience, the referencenumeral subscripts Y, M, C, and K will be omitted.

The process cartridges 5 each have the toner container 6. Furthermore,the process cartridge 5 has the photosensitive drum 1 which is an imagecarrier. Furthermore, the process cartridge 5 has the charging roller 2,the developing roller 3, the drum cleaning blade 4, and the waste tonercontainer 7.

The charging roller 2, by applying a voltage of a predetermined negativepolarity to the photosensitive drum 1, charges the surface of thephotosensitive drum 1 to the voltage of the predetermined negativepolarity. The laser unit 8 is disposed below the process cartridge 5,and the laser unit 8 performs exposure in relation to the photosensitivedrum 1 based on an image signal. As a result, an electrostatic latentimage is formed on the surface of the photosensitive drum 1. Thedeveloping roller 3 applies a voltage of a predetermined negativepolarity to the photosensitive drum 1 and then by supplying thephotosensitive drum 1 with toner that is accommodated in the tonercontainer 6, develops an electrostatic latent image. As a result, the Y,M, C, and K toner images are each formed on the surface of thephotosensitive drum 1. Note that the toner used in the presentembodiment is negatively charged.

An intermediate transfer member unit is configured by the intermediatetransfer member 11, the drive roller 12, the tension roller 13, and theopposing roller 15. Also, the primary transfer roller 10 is disposedinside the intermediate transfer member 11 facing the photosensitivedrum 1, and is of a configuration in which a transfer voltage is appliedby a voltage application unit (not shown). Each photosensitive drum 1and the intermediate transfer member 11 are rotated in the direction ofthe arrow and then by applying a positive voltage to the primarytransfer roller 10, the toner image that is formed on the photosensitivedrum 1 is primary-transferred onto the intermediate transfer member 11.The toner images on the photosensitive drums 1 are primary-transferredonto the intermediate transfer member 11 in the order of Y, M, C, and Kand then are conveyed to the secondary transfer roller 14 in a state inwhich the toner images of the four colors are overlapped. The toner thatis remaining on the photosensitive drum 1 after the primary transfer isscraped off by a cleaning blade 4 and then is accommodated in the wastetoner container 7.

The feeding mechanism 20 has the feeding roller 22 (feeding member) thatfeeds the recording material S to a conveyance path 40 from anaccommodation cassette (feeding cassette) 21 which accommodates therecording material S. Furthermore, the feeding mechanism 20 has theconveyance roller 23 (conveyance member) that conveys the fed recordingmaterial S and the separation roller 24 (separation member) thatseparates a plurality of the recording materials S into single sheetsand conveys the single sheets. The accommodation cassette 21 canattach/detach in relation to an apparatus main body 50 (printer housing)and is made so that the user can perform replenishment or replacement ofthe recording material S. Then, the recording material S that isconveyed from the feeding mechanism 20 is conveyed to the secondarytransfer roller 14 by the registration roller pair 25. In order totransfer the toner image from the intermediate transfer member 11 to therecording material S, a voltage of positive polarity is applied to thesecondary transfer roller 14. As a result, the toner image on theintermediate transfer member 11 is secondary transferred onto theconveyed recording material S. Then, the recording material S to whichthe toner image is transferred is conveyed to the fixing device 30 andis heated and pressurized by the fixing film 31 and the pressure roller32, and the toner image is fixed to the surface of the recordingmaterial S. The recording material S on which the toner image has beenfixed is discharged to the exterior of the apparatus main body 50 of theprinter PR by a discharging roller pair 33.

In a control unit 100, an MPU (not shown) comprising a CPU 70 and thelike; a RAM (not shown) that is used to calculate data that is necessaryfor controlling the printer PR, as a temporary storage, and the like; aROM (not shown) that stores a program for controlling the printer PR orvarious data are provided. In the conveyance path 40, the conveyancepath sensor 27 is disposed to detect the conveyed recording material S.When the conveyance path sensor 27 detects the recording material S, asignal that notifies accordingly is outputted to the control unit 100.The control unit 100 performs the overall control of theelectrophotographic process and determines whether or not conveyancefailure such as an early arrival, a delay, or a jam of the recordingmaterial S has occurred based on the signal that was notified from theconveyance path sensor 27. In a case where the control unit 100determines that conveyance failure has occurred, the control unit 100displays on an operation display unit 80 (operation panel) a message oran image for notifying the user that conveyance failure has occurred.Also, the control unit 100 displays on the operation display unit 80 amessage or an image that indicates a means for resolving the conveyancefailure as necessary.

[Description of Feeding Mechanism]

Next, the feeding mechanism 20 according to the present embodiment willbe described in detail using FIG. 25A to FIG. 25C. FIG. 25A to FIG. 25Care a schematic cross-sectional view that represents the feedingoperation in the present embodiment.

FIG. 25A is a cross-sectional view of the feeding mechanism 20 at atiming when the recording material S1, among a plurality of recordingmaterials S that are accommodated in the accommodation cassette 21, thatis positioned at the top is fed. The recording material S1 within theaccommodation cassette 21 is positioned by the trailing edge regulatingplate 26 within the accommodation cassette 21, and the leading edge ofthe recording material S1 when the recording material S1 is fed is atthe set position Ps in FIG. 25A. Here, the leading edge of the recordingmaterial S1 is an edge on the downstream side in the feeding directionof the recording material S1 and the trailing edge of the recordingmaterial S1 is an edge on the upstream side in the feeding direction ofthe recording material S1. When a pick start signal that is a triggerfor the feeding operation is outputted and then the feeding operation isstarted, the feeding roller 22 and the conveyance roller 23 each rotatein the direction of the arrows in FIG. 25A and the recording material S1is fed in the rightward direction in FIG. 25A due to the friction thatoccurs between the recording material S1 and the feeding roller 22.

Then, the recording material S1 reaches a separation nip portion Pnformed by the conveyance roller 23 and the separation roller 24. At thistime, as illustrated in FIG. 25B, frictional force also occurs betweenrecording materials S1 and S2, and the recording material S2 may alsomove. Hereinafter, this phenomenon is referred to as a multiple pickupphenomenon. The conveyance roller 23 and the separation roller 24 have afunction of, when two or more recording materials S are fed to theseparation nip portion Pn due to the multiple pickup phenomenon,separating the plurality of the recording materials S to single sheetsand then feeding downstream only the separated single sheet of therecording material S. A torque limiter (not shown) is connected to theseparation roller 24, and torque as a resistance force is applied in adirection opposite to the conveyance direction of the recording materialS1. This torque is set so that when there is only one recording materialS in the separation nip portion Pn, the separation roller 24 rotatesfollowing the conveyance roller 23, and when two or more recordingmaterials S enter the separation nip portion Pn, the separation roller24 stops. Accordingly, a plurality of recording materials S can beseparated and conveyed downstream one by one by the separation nipportion Pn.

Then, when the feeding roller 22 and the conveyance roller 23 furthercontinue to rotate, the recording material S1 passes through theregistration roller pair 25, and the leading edge of the recordingmaterial S1 reaches the position Pr where the leading edge is detectedby the conveyance path sensor 27 as illustrated in FIG. 25C. The timeelapsed from when the pick start signal that is the trigger for thefeeding operation was outputted until the recording material S1 reachesthe conveyance path sensor 27 is the feeding time. This feeding time ismeasured by the CPU 70 that is included in the control unit 100described in FIG. 24.

FIG. 26 is a graph that indicates the transition of the feeding timethat is related to the number of sheets fed which was monitored from thestart of the use of the printer PR. In continuing to use the printer PR,a roller friction coefficient changes subtly due to variability in thephysical properties (surface property, grammage, rigidity, and the like)of the medium used at each time or the difference in the temperature andhumidity of the usage environment. Therefore, feeding time changesirregularly. For example, how the tendency of the feeding time haschanged by the type of the recording material S changing (changed from arecording material E to another type of a recording material F) can beconfirmed at a timing D in FIG. 26. Note that the feeding reference timeTs and feeding reference time Tm will be described later in detail.

Generally, in a case where feeding is started from a state in which theleading edge of the recording material S is positioned at the separationnip portion Pn, the feeding time is shortened, and in a case where thefeeding time is started from a state in which the leading edge of therecording material S is positioned at a set position Ps, the feedingtime is lengthened. Because there is such a fundamental characteristic,irregular change in the feeding time within a predetermined range is notsomething that directly leads to feeding failure. Data that suddenlydeviates outward in relation to data distribution (feeding time datathat has changed beyond the predetermined range) may lead to feedingfailure. Accordingly, a reference value of the feeding time that issuitable for the state at each time is statistically calculated and byconsidering the difference tendency in relation to the data thatdeviates suddenly, an evaluation of failure risk is performed.

[Description of Method for Calculating Reference Value]

Next, a method for calculating the reference value of feeding time willbe described. Feeding time changes greatly in accordance with variousfactors such as a feeding inlet from where the recording material S isfed, the type of paper, environment, the status of the durability of themain body, and the method of setting paper by the user. Therefore, whencalculating the reference value, it is necessary to calculate usingcollection data that is statistically sufficient for being able toguarantee reliability and whose feeding time is stable. It is preferredto utilize the most recent data in order to remove the durability factorand to utilize data from which portions whose variation amount is largehas been removed. Also, a configuration may be taken so as to utilizeinformation (for example, sheet type sensor, temperature/humiditysensor, cassette opening/closing history, paper remaining amount sensor,and the like) that is held by the main body and remove data that is in asection whose usage condition has changed.

FIG. 27 is a graph for representing the frequency distribution of themost recent 500 sheet of feeding time data. In the present embodiment,this feeding time data for 500 sheets is handled as one set ofcollection data A0 and the reference value is calculated. In otherwords, one set of reference value data is calculated (updated) for every500 sheets from the start of use of the printer PR. Here, because thefeeding time may change in accordance with the remaining amount of therecording material S that is accommodated in the accommodation cassette21, correction processing in accordance with the remaining amount of therecording material S that is accommodated in the accommodation cassette21 in advance may be performed in relation to the collection data A0.Hereinafter, the reason for this and specific correction method will bedescribed.

When the remaining amount of the recording material S that isaccommodated in the accommodation cassette 21 decreases, a space isformed between the recording material S that is positioned at the topand the feeding roller 22; therefore, it is necessary to cause theintermediate plate to rise in order to fill this space. As a method forraising the intermediate plate, a rotation method (method for lifting upthe recording material S by rotating the intermediate plate) and alinear-motion method (method for lifting up the recording material S bymoving the intermediate plate in a vertical direction) are known. Out ofthese, when a configuration of the rotation method is taken, there is apossibility that the feeding time may also be affected in conjunctionwith the intermediate plate being rotated.

In the configuration of the rotation method, there are two major factorsthat can be considered as the reason why the feeding time changes. Thefirst factor is that the set position Ps (described in FIG. 25A to FIG.25C) of the recording material S that is positioned at the top changesin conjunction with the intermediate plate being rotated. By the setposition Ps deviating, the time it takes for the recording material S toarrive at the conveyance path sensor 27 changes. The second factor isthat the orientation (slope) of the recording material S that ispositioned at the top changes in conjunction with the intermediate platebeing rotated. Because the angle at which the recording material Senters the conveyance path 40 changes when the orientation of therecording material S changes, the path that the recording material Stakes from the separation nip portion Pn to a detection position Prchanges. The recording material S, when fully accommodated, is conveyedso that the leading edge of the recording material S follows the outerside (right side in FIG. 25A to FIG. 25C) of the conveyance path 40.Meanwhile, the recording materials S, when lightly accommodated, areconveyed so that the leading edge of the recording material S followsthe inner side (left side in FIG. 25A to FIG. 25C) of the conveyancepath 40. Considering the above factors, there is a tendency that, whenthe recording materials S are lightly accommodated in comparison to whenit is fully accommodated, the feeding time is shorter. This situation isindicated in FIG. 28.

In the printer PR, a mechanism that detects the remaining amount of therecording material S that is accommodated in the accommodation cassette21 is comprised. Specifically, a paper surface sensor (not shown) thatdetects the surface of the recording material S that is accommodated inthe accommodation cassette 21 is disposed in the printer PR and by thelift up time it takes for the paper surface sensor to detect therecording material S or the lift up driving amount being measured, theremaining amount can be detected. After the lift up, the remainingamount can be detected by the CPU 70 counting the number of sheets fed.In the present embodiment, correction processing is performed on thefeeding time in accordance with the detected remaining amount. Forexample, when the recording materials S is fully accommodated,correction processing is not performed; when the remaining amount isfrom 20% to 40%, a correction time α is added to the measured feedingtime; and when the remaining amount is from 0% to 20%, a correction timeβ (α<β) is added to the measured feeding time.

Note that as described above, when acquiring the collection data A0, itis preferred to utilize data from which portions whose variation amountis large has been removed; however, in a case where it is necessary touse data of a portion whose variation amount is large in order toacquire a sufficient number of samples, correction processing is appliedon the collection data A0 in advance. For example, as described in FIG.26, in a case where the type of the recording material S that isaccommodated in the accommodation cassette 21 is changed from therecording material E to the recording material F, the feeding time isslower in general. Considering this effect, in a case where data in acase where the recording material E is fed and data in a case where therecording material F is fed are present among feeding data for 500sheets, correction processing is performed so that a large differencewill not arise between the two sets of data. Specifically, processingsuch as adding a correction time γ in relation to data in a case wherethe recording material E is fed, subtracting the correction time γ inrelation to data in a case where the recording material F is fed, andthe like is performed.

In the present embodiment, in a case where the recording material S isfed by the feeding mechanism 20, the possibility that slipping may occuris determined. Slipping refers to a situation in which, when the feedingroller 22 feeds the recording material S, frictional force does not workproperty, slipping occurs, and the timing to move the recording materialS is delayed or the recording material S could not be moved. In thepresent embodiment, the feeding time when feeding is started from astate in which the leading edge of the recording material S1 is at theset position Ps in FIG. 25A to FIG. 25C is defined as the feedingreference time Ts (reference value). Then, an analysis is performed byextracting data that indicates time that is longer than this referencevalue.

In the frequency distribution in FIG. 27, the feeding reference time Tsis the top x % of values of the collection data A0 from which a portionof data that suddenly became slow is removed. In the present embodiment,after the distribution tendency of the feeding reference time Ts undervarious condition is confirmed, x=5%, which is a ratio in which thefeeding reference time Ts could be acquired in a stable manner under allconditions, is set. Note that it is known from experimentation that x %,even when large, is 10% or less (within a range of a few percent to10%).

[Method of Calculating Slip Index Value and Description of Method forDetermining Possibility that Slipping May Occur]

Next, a method for calculating a slip index value HS using the referencevalue will be described using FIG. 29. FIG. 29 is a graph for indicatingthe relationship between the number of sheets fed and feeding time ofthe collection data A0. Note that here, in order to make the grapheasier to view, not all of the data for 500 sheets have been plotted.The white circle data on the graph is data that indicates times (delayeddata) that are longer than the feeding reference time Ts. When atendency to slip in the feeding mechanism 20 due to durabilitytransition, the state of the surface property of the recording materialS, and the like starts to appear, the level of delay in the white circledata on the graph becomes larger. In view of this tendency, the averagevalue of the absolute value of the differences from the feedingreference time Ts to the white circle data are set as the slip indexvalue HS. In other words, the slip index value HS is obtained by thefollowing expression.

$\begin{matrix}{H_{s} = \frac{ {\sum_{i = 1}^{N}H_{si}} )}{N}} & {{Expression}\mspace{14mu}(7)}\end{matrix}$

Although here the absolute values of the differences were averaged as amethod for quantifying the index value, other parameters such as asimple sum total of the absolute values of differences and a root meansquare may be used. One of this slip index value HS is calculated forevery feeding time data (collection data A0) for 500 sheets. Note thatthis slip index value HS is acquired by the CPU 70 that is included inthe control unit 100.

Next, a method for determining the possibility that slipping may occurwill be described using FIG. 30. FIG. 30 is a result of calculating theslip index value HS for every 500 sheets from the start of the use ofthe printer PR made into a graph. It can be seen how the slip indexvalue HS gradually becomes larger in accordance with the increase in thenumber of sheets fed. In the present embodiment, two thresholds, HSA andHSB are prepared and the possibility that slipping may occur isdetermined by the control unit 100 as follows.

HS≤HSA: Possibility that slipping may occur is low

HSA<HS≤HSB: Possibility that slipping may occur is normal

HSB<HS: Possibility that slipping may occur is high

Thresholds are not limited to the two, and three or more thresholds maybe prepared in accordance with the intended use. The control unit 100may notify the acquired determination result in relation to the user orthe administrator who performs the maintenance management service of theprinter PR. Note that, in a case where a notification is performed, thecontrol unit 100 performs in real time the determination of which abovestate the feeding mechanism 20 is in and then performs notification inrelation to the user or administrator each time. As the number of sheetsfed increases, the feeding roller 22 is abraded, and if the possibilitythat slipping may occur is high, the frequency of notification will alsoincrease.

FIG. 31 is a flowchart for determining the possibility that slipping mayoccur in the present embodiment. The control based on FIG. 31 isexecuted by the CPU 70 based on a program that is stored in the ROM (notshown) and the like which are provided in the control unit 100. Notethat the CPU 70 executes this control every time feeding time data(collection data A0) for 500 sheets is acquired.

First, the CPU 70 acquires the feeding reference time Ts which is thetop x % of values of the collection data A0 (step S10). Next, the CPU 70obtains the slip index value HS based on an expression described above(step S11). The CPU 70 compares the slip index value HS and the presetthreshold HSA (step S12) and if the slip index value HS is equal to orless than the threshold HSA, the CPU 70 determines that, in case wherethe recording material S is fed by the feeding mechanism 20, thepossibility that slipping may occur is low (step S14). In a case wherethe slip index value HS is greater than the threshold HSA, the CPU 70next compares the slip index value HS and the preset threshold HSB(HSA<HSB) (step S13). If the slip index value HS is equal to or lessthan threshold HSB, the CPU 70 determines that, in a case where therecording material S is fed by the feeding mechanism 20, the possibilitythat slipping may occur is normal (step S15). If the slip index value HSis larger than threshold HSB, the CPU 70 determines that, in a casewhere the recording material S is fed by the feeding mechanism 20, thepossibility that slipping may occur is high (step S16). In a case wherethe possibility that slipping may occur is determined to be high, theCPU 70 determines that the remaining life time of the feeding roller 22that is included in the feeding mechanism 20 is running short andprompts the user or administrator via the operation display unit 80 toreplace the feeding roller 22 (step S17).

Finally, the control of the present flowchart is ended.

By the above, by virtue of the present embodiment, it becomes possibleto determine accurately the possibility that slipping may occur when thefeeding unit feeds the recording material.

Note that, in the present embodiment, the CPU 70 determines thepossibility that slipping may occur and in a case it determines that thepossibility that slipping may occur is high, determines that theremaining life time of the feeding roller 22 is running short. However,the present invention is not limited to this. The CPU 70 may determinethat the remaining life time of the feeding roller 22 is running shortdirectly from the value of the slip index value HS without determiningthe possibility that slipping may occur. In other words, the CPU 70, ina case where the slip index value HS is greater than the threshold HSB,determines that the remaining life time of the feeding roller 22 isrunning short.

Sixth Embodiment

In the present embodiment, description will be given regarding a methodfor determining the possibility that the recording materials may bedouble fed during the feeding operation. The description of the mainparts are the same as that of the fifth embodiment and here, only partsthat are different from the fifth embodiment will be described.

[Description of Method for Calculating Reference Value]

In the present embodiment, in a case where the recording material S isfed by the feeding mechanism 20, the possibility that double feeding mayoccur is determined. Double feeding refers to a state in which therecording material S2 that is accommodated under the recording materialS1 is picked up due to the friction that is generated between therecording material S2 and the recording material S1 during the feedingoperation of the recording material S1 and then the leading edge of therecording material S2, in a state in which it is overlapping therecording material S1, goes past the separation nip portion Pn. In thepresent embodiment, the feeding time when feeding is started from astate in which the leading edge of the recording material S1 is at theseparation nip portion Pn in FIG. 25A to FIG. 25C is defined as thefeeding reference time Tm (reference value). Then, an analysis isperformed by extracting data that indicates time that is shorter thanthis reference value.

A method for calculating the feeding reference time Tm is describedusing FIG. 32. FIG. 32 is a graph for representing the frequencydistribution of feeding time data like FIG. 27. Here, similarly to inthe fifth embodiment, because the feeding time may change in accordancewith the remaining amount of the recording material S that isaccommodated in the accommodation cassette 21, correction processing inaccordance with the remaining amount of the recording material S that isaccommodated in the accommodation cassette 21 in advance may beperformed in relation to the collection data A0.

Here, when frequency distribution in FIG. 32 is viewed, it can be seenthat the feeding time data is divided roughly into two groups. In viewof the configuration of the feeding mechanism 20, the position of theleading edge of the recording material S that is accommodated in theaccommodation cassette 21 has a high probability of being present at theset position Ps or the separation nip portion Pn. Also, in a state inwhich the leading edge of the recording material S is at the setposition Ps, the distance from the leading edge of the recordingmaterial S to the conveyance path sensor 27 is longer in comparison to astate in which the leading edge of the recording material S is at theseparation nip portion Pn. Therefore, a group (subset A1) whose lengthof time is shorter corresponds to the feeding time data in a state inwhich the leading edge of the recording material S1 is at the separationnip portion Pn. Also, a group (subset A2) whose length of time is longercorresponds to the feeding time data in a state in which the leadingedge of the recording material S1 is at the separation nip portion Pn.

In the present embodiment, a data separation algorithm is applied inrelation to the collection data A0 and only the configuration data of asubset A1 is extracted. In the present embodiment, separation processingis performed using a Gaussian mixture model. The Gaussian mixture modelis a model that approximates data by superimposing a plurality ofGaussian distribution (normal distribution). Note that other clusteringmethods such as a k-means method may be used. In the extracted subsetA1, due to the characteristics of the feeding mechanism 20, the peak ofthe distribution appears at the feeding time that corresponds to a statein which the leading edge of the recording material S is at theseparation nip portion Pn where the succeeding paper that was picked upis obstructed and stopped. The possibility that double feeding may occurneeds to be determined using the feeding time data of the recordingmaterial S which was not obstructed or stopped at the separation nipportion Pn; therefore, the feeding time (feeding time whose frequency isthe highest) of the peak of the distribution of the subset A1 is set tothe feeding reference time Tm. Note that although this time, the feedingreference time Tm is set to the peak of the distribution of the subsetdata A1, it may be the average value or the median value of the feedingtime data that is included in the subset A1.

[Method of Calculating Double Feeding Index Value and Description ofMethod for Determining Possibility that Double Feed May Occur]

Next, a method for calculating a double feeding index value Hm using thereference value will be described using FIG. 33. FIG. 33 is a graph forindicating the relationship between the number of sheets fed and feedingtime of the collection data A0. Note that here, in order to make thegraph easier to view, not all of the data for 500 sheets have beenplotted. The white circle data (early arrival data) on the graph is datathat indicates times that are shorter than the feeding reference timeTm. When a tendency to double feed in the feeding mechanism 20 due todurability transition, state of the surface property of the recordingmaterial, and the like starts to appear, occurrence frequency of casesin which the succeeding sheets are not obstructed or stopped at theseparation nip portion Pn increases. Therefore, the number of whitecircle data on the graph increases and the difference from the feedingreference time Tm also increases. In view of this tendency, the rootmean square of the differences from the feeding reference time Tm to thewhite circle data are set as the double feeding index value Hm. In otherwords, the double feeding index value Hm is obtained by the followingexpression.

$\begin{matrix}{H_{m} = \sqrt{\frac{\sum_{i = 1}^{N}H_{mi}^{2}}{N}}} & {{Expression}\mspace{14mu}(8)}\end{matrix}$

Although here the absolute values of the differences were averaged as amethod for quantifying the index value, other parameters such as asimple sum total of the absolute values of differences and a root meansquare may be used. One of this double feeding index value Hm iscalculated for every feeding time data (collection data A0) for 500sheets. Note that this double feeding index value Hm is acquired by theCPU 70 that is included in the control unit 100.

Next, a method for determining the possibility that double feeding mayoccur will be described using FIG. 34. FIG. 34 is a result ofcalculating the double feeding index value Hm for every 500 sheets fromthe start of the use of the printer PR made into a graph. In the presentembodiment, two thresholds, HmA and HmB are prepared and the possibilitythat double feeding may occur is determined by the control unit 100 asfollows.

Hm≤HmA: Possibility that double feeding may occur is low

HmA<Hm≤HmB: Possibility that double feeding may occur is normal

HmB<Hm: Possibility that double feeding may occur is high

Thresholds are not limited to the two, and three or more thresholds maybe prepared in accordance with the intended use. The control unit 100may notify the acquired determination result in relation to the user orthe administrator who performs the maintenance management service of theprinter PR. Note that the double feeding index value Hm as indicated inFIG. 34 is different from the slip index value Hs in the fifthembodiment and does not worsen as the durability progresses. The doublefeeding index value Hm is highly dependent on the surface property(frictional coefficient) of the recording material S and it is knownthat this surface property is different between the types of therecording material S, of course, and is also different between the lotsand books of paper even if the type of paper is the same. By mainlynotifying the dealer of such information, it becomes possible for thedealer to provide a better quality service such as introducing adifferent type of the recording material S for the user who is using theprinter PR under an environment in which double feeding is likely tooccur.

FIG. 35 is a flowchart for determining the possibility of double feedingoccurring in the present embodiment. The control based on FIG. 35 isexecuted by the CPU 70 based on a program that is stored in the ROM (notshown) and the like which are provided in the control unit 100. Notethat the CPU 70 executes this control every time feeding time data(collection data A0) for 500 sheets is acquired.

First, the CPU 70 divides the collection data A0 into two groups(subsets A1 and A2) (step S20). The CPU 70 selects the group whose timeis shorter (subset A1) among the two groups (step S21). Then, the CPU 70obtains the feeding reference time Tm from the feeding time data that isincluded in the group whose time is shorter (step S22). Next, the CPU 70obtains a double feeding index value Hm based on an expression describedabove (step S23). The CPU 70 compares the double feeding index value Hmand the preset threshold HmA (step S24) and if the double feeding indexvalue Hm equal to or less than the threshold HmA, the CPU 70 determinesthat, in case where the recording material S is fed by the feedingmechanism 20, the possibility that double feeding may occur is low (stepS26). In a case where the double feeding index value Hm is greater thanthe threshold HmA, the CPU 70 next compares the double feeding indexvalue Hm and the preset threshold Hm (HmA<HmB) (step S25). If the doublefeeding index value Hm is equal to or less than threshold HmB, the CPU70 determines that, in a case where the recording material S is fed bythe feeding mechanism 20, the possibility that double feeding may occuris normal (step S27). In a case where the double feeding index value Hmis larger than threshold HmB, the CPU 70 determines that, in a casewhere the recording material S is fed by the feeding mechanism 20, thepossibility that double feeding may occur is high (step S28). Finally,the control of the present flowchart is ended. Note that as describedabove, the double feeding index value Hm does not worsen as thedurability progresses; therefore, in the present embodiment, in a casewhere it is determined that the possibility that double feeding mayoccur is high, the end of the life of the roller is not notified by theCPU 70.

By the above, by virtue of the present embodiment, it becomes possibleto determine accurately the possibility that double feeding may occurwhen the feeding unit feeds the recording material.

Note that the possibility that slipping may occur and the possibilitythat double feeding may occur are being determined in the above fifthand sixth embodiments, respectively; however, a configuration may betaken so that the possibility that slipping may occur and thepossibility that double feeding may occur may both be determined andthen notified together to the user or dealer.

[Variation]

In the above first to sixth embodiments, the feeding mechanism 20 hadthe feeding roller 22, the conveyance roller 23, and the separationroller 24. However, the present invention is not limited to this. Forexample, a configuration may be taken so as to dispose one feedingroller, whose size is larger in comparison to the feeding roller 22, inwhich a first position on its surface contacts the recording material Sthat is accommodated in the feeding cassette 21 and a second position onits surface forms a separation nip portion with the separation roller24. In other words, the conveyance roller 23 is unnecessarily accordingto this configuration.

Also, although in the above first to sixth embodiments, the counting ofthe feeding time was started from the timing when the feeding roller 22started the feeding of the recording material S, the present inventionis not limited to this. For example, a configuration may be taken sothat a new sensor is disposed at a position that is different from theconveyance path sensor 27 and the counting of the feeding time isstarted from the timing when that new sensor has detected the recordingmaterial S. Alternatively, a configuration may be taken so that thecounting of the feeding time is started from the timing that therecording material S is detected by the conveyance path sensor 27 andthe counting of the feeding time is ended at the timing that therecording material S is detected by the new sensor.

Also, although in the above fifth embodiment, the feeding reference timeTs is extracted as the top x % values of the collection data A0, thepresent invention is not limited to this. Similarly to the sixthembodiment, a configuration may be taken so as to divide the collectiondata A0 into two groups (subsets A1 and A2), select the group A2 whosetime is longer, and then acquire the feeding reference time Ts.Specifically, similarly to the method that was described in the sixthembodiment, the feeding time (feeding time whose frequency is thehighest) of the peak of the distribution of the group A2 may be set asthe feeding reference time Ts or the average value or the median valueof the feeding time data that is included in the group A2 may be set asthe feeding reference time Ts.

Also, although in the above sixth embodiment, the feeding reference timeTm is extracted from the feeding time data included in the group A1, thepresent invention is not limited to this. Similarly to the fifthembodiment, the feeding reference time Tm may be acquired as the bottomy % values of the collection data A0. A smaller value than x % needs tobe set for y %, and according to experimentation, it is desirable to seta value from 1% to 2%.

Also, in the above fifth and sixth embodiments, the possibility that anabnormal state may occur when the feeding mechanism 20 feeds therecording material S is determined; however, the present invention mayalso be applied to a location besides the feeding mechanism 20. Forexample, by monitoring the feeding time between desired two points thaton the conveyance path 40 positioned further on the downstream side thanthe feeding mechanism 20, it becomes possible to determine thepossibility that a sudden slip may occur due to a change in conveyanceload which may occur when the recording material S passes that section.

Also, although in the above fifth and sixth embodiments, the feedingtime is utilized as the processing data for determining the possibilitythat the abnormal state may occur, the present invention is not limitedto this. For example, the driving amount by the motor (actuator) thatdrives the feeding roller 22 or the conveyance roller 23 may be utilizedas the processing data. As the reference amount, the driving amount datawhich will be the reference in place of the feeding reference time Tsand the feeding reference time Tm is obtained, a total sum of theabsolute values of the differences and the like is obtained in the samemethod as described in the fifth and second embodiments, and then theresult is compared with the threshold. If the driving amount is utilizedas the processing data, it is possible to support cases in which controlfor switching the conveyance speed of the recording material S isperformed after the recording material S is fed by the feeding roller22.

Also, although in the above fifth and sixth embodiments, the CPU 70 thatis disposed in the printer PR determines the possibility that anabnormal state such as slipping or double feeding may occur, the presentinvention is not limited to this. As the configuration that wasdescribed in the first to fourth embodiments, a configuration may betaken so as to determine the possibility that an abnormal state mayoccur by exchanging information between the image forming apparatus 100and the server 410. Specifically, a configuration may be taken so thatthe CPU 70 transmits the feeding time data to the server that isconnected with the printer PR and then the CPU that is disposed on theserver executes the flowchart that is indicated in FIGS. 31 and 35.

Other Embodiments

By virtue of the present invention, by predicting the remaining lifetime of the feeding unit based on the usage state of the feeding unit,there is the effect of being able to ascertain the replacement timing ofthe feeding unit at an early stage.

Embodiment(s) of the present invention can also be realized by acomputer of a system or apparatus that reads out and executes computerexecutable instructions (e.g., one or more programs) recorded on astorage medium (which may also be referred to more fully as a‘non-transitory computer-readable storage medium’) to perform thefunctions of one or more of the above-described embodiment(s) and/orthat includes one or more circuits (e.g., application specificintegrated circuit (ASIC)) for performing the functions of one or moreof the above-described embodiment(s), and by a method performed by thecomputer of the system or apparatus by, for example, reading out andexecuting the computer executable instructions from the storage mediumto perform the functions of one or more of the above-describedembodiment(s) and/or controlling the one or more circuits to perform thefunctions of one or more of the above-described embodiment(s). Thecomputer may comprise one or more processors (e.g., central processingunit (CPU), micro processing unit (MPU)) and may include a network ofseparate computers or separate processors to read out and execute thecomputer executable instructions. The computer executable instructionsmay be provided to the computer, for example, from a network or thestorage medium. The storage medium may include, for example, one or moreof a hard disk, a random-access memory (RAM), a read only memory (ROM),a storage of distributed computing systems, an optical disk (such as acompact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™),a flash memory device, a memory card, and the like.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Application No.2019-224024, filed Dec. 11, 2019, Japanese Patent Application No.2020-104674, filed Jun. 17, 2020 and Japanese Patent Application No.2020-196336, filed Nov. 26, 2020 which are hereby incorporated byreference herein in their entirety.

1. An image forming system comprising: an information processingapparatus and an image forming apparatus, wherein the image formingapparatus comprises an accommodating unit configured to accommodate arecording material; a feeding unit configured to feed a recordingmaterial accommodated in the accommodating unit; a detection unitconfigured to detect a recording material fed by the feeding unit; and ameasuring unit configured to measure time from a predetermined timinguntil the detection unit detects the recording material, and theinformation processing apparatus comprises a reception unit configuredto receive time data obtained by the measuring unit from the imageforming apparatus; a classification unit configured to classify aplurality of the time data received by the reception unit into a firstgroup and a second group in accordance with a length of time; and aselection unit configured to select a group for predicting a remaininglife time of the feeding unit from the first group and the second groupthat are classified by the classification unit; and a prediction unitconfigured to predict a remaining life time of the feeding unit usingthe time data included in the group selected by the selection unit.2.-37. (canceled)